The presence of potassium oxide (K 2 O) and sodium oxide (Na 2 O) causes high reduction swelling of pellets of Bayan Obo iron concentrate during reduction and thus affects the permeability of blast gases during blast furnace operations. The influencing mechanism of K 2 O and Na 2 O on the swelling behavior of reduction reactions (1) Fe 2 O 3 → Fe 3 O 4 , (2) Fe 3 O 4 → Fe x O, and (3) Fe x O → Fe was researched by adding (K 2 O + Na 2 O) to Australian fine ore briquettes. The mineral composition and structure of the briquettes, as well as the reduction swelling after the three reactions coupled with the morphology and lattice parameters of the reduced products, were studied. From the results, the swelling index with 0.6% (K 2 O + Na 2 O) added was 8.52%, 7.91%, and 33.81%, respectively, and without were 12.36%, 3.27%, and 12.61%, respectively, for the three reactions. The swelling index of the first reaction (Fe 2 O 3 → Fe 3 O 4 ) is reduced because alkali metal suppresses crystal cracking. The swelling mainly occurs at the third stage (Fe x O → Fe), because K 2 O and Na 2 O enhance the oriented growth of iron whiskers, as well as make them smaller. Crystal transformation does not occur at the second stage (Fe 3 O 4 → Fe x O) and the reduction swelling is small, but the swelling index of the briquettes with added with K 2 O and Na 2 O increases (7.91% compared to 3.27%). The main reason is that the alkali metal reduces the melting point of the slag phase and promotes the cascade crystallization of FeO. Therefore, the abnormal swelling of briquettes caused by K and Na is mainly caused by the growth of iron whiskers at the third stage.

中文翻译：

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K和Na对氧化焙烧煤球还原溶胀性能的影响

氧化钾 (K 2 O) 和氧化钠 (Na 2 O) 的存在会导致白云鄂博铁精矿球团在还原过程中发生高度还原膨胀，从而影响高炉操作过程中鼓风气体的渗透性。K 2 O 和 Na 2 O 对还原反应溶胀行为的影响机理 (1) Fe 2 O 3 → Fe 3 O 4 ，(2) Fe 3 O 4 → Fe x O，(3) Fe x O → 通过将 (K 2 O + Na 2 O) 添加到澳大利亚细矿压块中来研究 Fe。研究了煤球的矿物组成和结构，以及三个反应后的还原溶胀以及还原产物的形态和晶格参数。从结果来看，添加0.6%（K 2 O + Na 2 O）的溶胀指数分别为8.52%、7.91%和33.81%，不添加的溶胀指数分别为12.36%、3.27%和12.61%，为三个反应。由于碱金属抑制晶体破裂，第一反应（Fe 2 O 3 → Fe 3 O 4 ）的溶胀指数降低。溶胀主要发生在第三阶段（Fe x O → Fe），因为 K 2 O 和 Na 2 O 促进了铁晶须的定向生长，并使它们变小。在第二阶段（Fe 3 O 4 → Fe x O）不发生晶体转变，还原溶胀很小，但添加 K 2 O 和 Na 2 O 的煤球溶胀指数增加（7.91% 与 3.27 相比） %）。主要原因是碱金属降低了渣相的熔点，促进了FeO的级联结晶。因此，K和Na引起的煤球异常膨胀主要是由于第三阶段铁晶须的生长引起的。由于碱金属抑制晶体破裂，第一反应（Fe 2 O 3 → Fe 3 O 4 ）的溶胀指数降低。溶胀主要发生在第三阶段（Fe x O → Fe），因为 K 2 O 和 Na 2 O 促进了铁晶须的定向生长，并使它们变小。在第二阶段（Fe 3 O 4 → Fe x O）不发生晶体转变，还原溶胀很小，但添加 K 2 O 和 Na 2 O 的煤球溶胀指数增加（7.91% 与 3.27 相比） %）。主要原因是碱金属降低了渣相的熔点，促进了FeO的级联结晶。因此，K和Na引起的煤球异常膨胀主要是由于第三阶段铁晶须的生长引起的。由于碱金属抑制晶体破裂，第一反应（Fe 2 O 3 → Fe 3 O 4 ）的溶胀指数降低。溶胀主要发生在第三阶段（Fe x O → Fe），因为 K 2 O 和 Na 2 O 促进了铁晶须的定向生长，并使它们变小。在第二阶段（Fe 3 O 4 → Fe x O）不发生晶体转变，还原溶胀很小，但添加 K 2 O 和 Na 2 O 的煤球溶胀指数增加（7.91% 与 3.27 相比） %）。主要原因是碱金属降低了渣相的熔点，促进了FeO的级联结晶。因此，K和Na引起的煤球异常膨胀主要是由于第三阶段铁晶须的生长引起的。